5W20 VS 5W30.........Again!

[BlueOvalFitter]

The 4.2 V6 in my 07 F150 was built 1997-2008. In all those years of production the tolerances and clearances had NEVER changed. Up until 1999 the spec'd oil was 5W30. In 2000 Ford spec'd 5W20 for CAFE reasons ONLY. In the 159K miles on my engine since new I have used 5W30 about 90% of the time. And, I can't tell the difference between that and 5W20. I have also used 0W40 a few times and couldn't tell the difference with that oil either.

I'm sorry about this one sentence in my reply. I was so caught up in my reply and wanting to get it posted that I forgot something. The 0W40 I used was EURO Castrol. For some reason it made my engine run somewhat more quiet then the other weight oils I had used. Maybe because Castrol oil is thicker? When my engine got up to operating temperature the thicker 40 weight made it quiet? My engine has never made any loud valve train noise with 5W20 and 5W30 oils. I can't explain it. But, I have always believed that all Castrol oils were somewhat thicker then other oil.

 

[BlueOvalFitter]

I found this very interesting article while doing some research on my own thread/post here. It gave me a better understanding of oil viscosities, and motor/engine oil in general.

Classic Mini Engine Oil, 20w-50, 5l Jug

www.minimania.com

 

[ZeeOSix]

Are more people using 5W20 more today than 5W30, OR, vise versa? And, why?

More people are using xW-20 because CAFE has forced the car companies to brainwash car owners into thinking that you "have to" use xW-20.

 

[CR94]

More people are using xW-20 because CAFE has forced the car companies to brainwash car owners into thinking that you "have to" use xW-20.

... And it's utterly impossible that Vehicle A, as used by Driver A, could possibly have a safer margin of MOFT than Vehicle B, as used by Driver B, when the oil in Vehicle B has a whopping 12% higher HTHS viscosity?

 

[Jimmy_Russells]

... And it's utterly impossible that Vehicle A, as used by Driver A, could possibly have a safer margin of MOFT than Vehicle B, as used by Driver B, when the oil in Vehicle B has a whopping 12% higher HTHS viscosity?

A fifteen foot ladder is way better than a twelve foot ladder when you have to get out of a ten foot hole, you know.

 

[ZeeOSix]

I found this very interesting article while doing some research on my own thread/post here. It gave me a better understanding of oil viscosities, and motor/engine oil in general.

Classic Mini Engine Oil, 20w-50, 5l Jug

www.minimania.com

From the write-up:
"It is time to introduce the concept of lubrication. Most believe that pressure = lubrication. This is false. Flow = lubrication. If pressure was the thing that somehow lubricated your engine then we would all be using 90 grade oil. Lubrication is used to separate moving parts, to keep them from touching. There is a one to one relationship between flow and separation. If you double the flow you will double the separation pressure in a bearing. The pressure at the bearing entrance is irrelevant.

In fact the relationship between pressure and flow is in opposition. If you change your oil to a thicker formula the pressure will go up. It goes up because the resistance to flow is greater and in fact the flow must go down in order for the pressure to go up. They are inversely related. Conversely if you choose a thinner oil then the pressure will go down. This can only occur if the flow has increased."

Bearing "separation pressure" doesn't depend on the flow through the bearing - it depends on the physical dimensions of the bearing, rotational speed and the oil viscosity which determines how much the oil wedge squeezes down in use (the MOFT), and therefore the resulting pressure in the separating oil MOFT wedge. A journal bearing will only flow what it's physical dimensions, rotational speed and oil viscosity will allow. On top of that there is some added flow through the bearing due to the positive displacement pump supply pressure at the bearing entrance which doesn't effect the MOFT, but does effect the flow beyond what the bearing wants to naturally flow due to dimensions and speed, which can help reduce the temperature rise in the bearing.

With a positive displacement oil pump not in pressure relief, the flow basically stays the same at any given engine RPM, so there is no situation where the "flow must go down in order for the pressure to go up". No matter what the oil viscosity is, any time the flow goes down the pressure must also go down. If you have a thinner oil, the pressure goes down because there is less resistance to move the same oil volume through the same circuit ... it doesn't go down because the "flow has increased". If the flow did increase at constant X viscosity, then the pressure would have to also go up. The pressure will go down if the viscosity goes down with the flow held constant.

 

[raburn2906]

5W30 in my 2008 F150 4.6l

 

[kschachn]

Yeah that linked article is full of misconceptions and incorrect information.

 

[kr_bitog]

I just changed M1 EP 0w20 out at around 5k miles and put in M1 EP 5w30 just for curiosity. It has without question made my car a bit more sluggish. Other than that I'll have to wait until next spring to sample it and find out how it holds up.

In my toyota and subaru i can tell the sluggishness between w20 and w30 oil, i believe it really determined by engine design. Engine designed for w20 oil really have tighter tolerance on built. This even more pronounced on small motorbike engine, when I change from w40 to w30, it improve the response and morning idle rpm significantly.

 

[silversport]

2007 Ford F150 5.4 3V with the usual engine issues...5W20 synthetic blend is what is supposed to go in the crankcase and when I received this unloved by the previous owner truck I changed to 5W20 full synthetic...prior to my stewardship of this truck it would stall sometimes while idling in stop and go traffic or drive through lines...I suffered this issue several times in the first 6 months of ownership...

I had read on the F150 Forum that the trucks run better with 5W30 (as well as a high volume oil pump replacement) so at the required time I replaced that oil with 5W30 full synthetic and I have not had the stall issue return ever in more than 18 months...

this truck is not a daily driver and I hit the time long before the mileage, I change around 3K miles but more than 6 months or at about the time I notice that the oil level drops slightly...2 years and about 10K miles without a stall in stop and go or drive through (or anywhere)...

to be sure the engine needs work but Ford claimed it needed a new engine (why the original owner got rid of it) and throwing some love it's way, the truck has run just fine other than the diesel like noise...

anyway...I think the 5W30 made a difference boosting the oil pressure slightly...

 

[ARCOgraphite]

Ah, 4 cylinder. I understand now.

Nope. It killed the power on my 2001 Mustang Bullitt too. Really bad. But that engine was new and tight.
The Lincoln Dealer didnt even have 5W20 and they put in 5W30. This was back in 2001.
I noticed it immediately - and that engine didnt even have VVT - it was the old Modular.

But if YOU don't feel a problem or see a significant mileage hit then I see no problem going to a 5W20 to a 5W30

But likely much of that 5W30 "thickness" is a "plastic" goo that may eventually produce varnish and stuck rings

Here is an example of a VII additive:

AFTON Viscosity Index Improver